WASHINGTON -- John Maine insists he’s not injured. Jerry Manuel doesn’t believe him for a second.

That, in essence, is what led to the heated argument between the two in the Mets’ dugout Thursday, when Manuel pulled Maine after just five pitches in a 10-7 win over the Nationals. And that’s why Maine was still fuming more than three hours later.

Manuel said Maine’s unusually low velocity led him to believe that something was physically wrong with him and that, at the very least, he would not be competitive against the Nationals.

But Maine said he was not in any pain and strongly criticized Manuel for not being more patient with him, and for not asking him how he felt before bringing in Raul Valdes from the bullpen.

“There’s no reason I should be seeing a (expletive) doctor tomorrow,” Maine said. “I feel something all the time. We’re pitchers. Every pitcher does.”

The doctors will be the ultimate judge of Maine’s health. But neither Manuel nor pitching coach Dan Warthen were willing to take Maine’s word for it.

“John is a habitual liar in a lot of ways as far as his own health,” Warthen said. “He’s a competitor and a warrior and he wants to go out there and pitch. But we have to be smart enough to realize this guy isn’t right. The ball isn’t coming out of his hands correctly.”

Coming off shoulder injuries the last two years, Maine (1-3, 6.13 ERA) has had a tumultuous season. He was on the verge of being bounced from the rotation after his first two starts. He was pulled from one start with pain in his non-throwing elbow. He threw 12 consecutive balls to begin his previous outing at Florida, in which he allowed six runs in five innings.

Now this.

The trouble Thursday started when Maine was warming up in the bullpen before the game. Warthen said Maine was struggling to hit 80 mph on the radar gun. The Mets decided to let him start the game anyway, but they had Valdes warming up before Maine even threw his first pitch.

When none of Maine’s first five pitches were clocked above 85 mph, Manuel decided he had seen enough.

“I thought that he would hurt himself trying to pitch at that velocity,” Manuel said. “I didn’t think it would be good for him as well as the team.”

But Maine was upset about being pulled so quickly simply because his velocity was down.

“Me throwing 85 mph I don’t think is a good explanation to be taken out of the game,” he said. “It was the first batter of the game. Cut me a little bit of slack. The last couple pitches started getting back to normal.”

It’s not clear yet what Maine’s status is for his next start. But whatever happens, the relationship between Maine and Manuel has been strained.

The second week of the season, Maine was upset when Manuel floated the idea of pulling him from the rotation with reporters before talking to him about it. Now, Maine is livid with him.